Two kinds of potentiality: a critique of McGinn on the ethics of abortion

In Moral Literacy, or How to Do the Right Thing , Colin McGinn proposes a consequentialist solution to the abortion dilemma. McGinn interprets moral rights and moral interests as attributable only to actually sentient beings by virtue of their ability to experience pleasure or pain. McGinn argues against the moral rights of potentially conscious human fetuses, on the grounds that the unjoined ova and spermatazoa of any fertile men and women are also potentially sentient, but we do not generally suppose that unjoined human genetic germ plasm has moral rights. I argue that McGinn's reply equivocates between two different senses of 'potential sentience'. I distinguish between strong and weak potentiality, or between naturally probable potentiality and merely logically possible potentiality . I agree that it is reasonable to deny that a weak or merely logically possible potentially sentient fetus that would result from any unjoined ovum and sperm has a moral right to life. But I claim that this fact does not diminish the plausibility of extending a moral right or potential moral right to life to a naturally probable potentially sentient fetus, which we have good reason to believe will actually become sentient in the natural course of things if nothing is done to prevent its normal development. I conclude that it is not merely the potentiality, but the strong potentiality of a healthy, normally developing fetus that is soon to acquire sentience, moral interests, and, on McGinn's own terms, a moral right to life, that continues to sustain the abortion contro-versy, even among those who also want respect a woman's moral right to reproductive self-determination.